rowiac

Have you already tried a smaller Line Width in Cura? I've adjusted that down to 0.3mm in the past to improve text or print small features that disappear during slicing. It looks like Cura will allow you to adjust a 0.4mm nozzle's line width down to 0.26mm before it complains (turns the field orange as a warning), for a UMO+ anyway.

@gr5: I'd be interested in learning more about this technique.

For cheap super glue, try Harbor Freight: 10-pack of small tubes for $3.99. https://www.harborfreight.com/10-piece-super-glue-gel-68349.html Or maybe a local dollar store. Personally for PLA I prefer Plastruct Plastic Weld (thin liquid) for tight fitting surfaces and SciGrip 16 (medium bodied cement) if there are rough surfaces or some gaps.

@kmanstudios I've had good luck with Gizmo Dorks wood filament. It's a little bit brittle, but works fine with careful handling. You are supposed to be able to get different wood colors depending on how hot you run it, but I've found that I need to run it at 230°C to get good adhesion between layers. After printing I apply Old English Scratch Cover, let it soak in and wipe off the excess to darken it and that makes it look more like wood.

In you are in the USA, fbrc8.com has OEM replacement main boards--they are not cheap though. If you live somewhere else you will need to find who supports Ultimaker there. You could also try Aliexpress but the quality of the board would be questionable.

@kmanstudios, I'm trying to figure out what is this "B4Artists" that you mention. Couldn't find it on Google. Do you have a link so I can check it out?

By ball bearings I mean the two linear bearings in the print head that the two shafts go through. Unlike the bronze bushings on the X and Y axles, these bearings have recirculating balls in them, hence my use of the term "ball bearings", sorry for the confusion. I just wanted to make sure that these weren't sticking, and it sounds like you have checked that.

So aside from the possible replacement of the belts and the mainboard that have been already suggested, have you checked an obvious thing like making sure the print head moves in the Y-direction freely? Maybe the shafts with the bronze bushings are dry and/or dirty--it sort of looks like that from one of your pictures. How about the linear ball bearings in the print head--do they move freely?

Glad you got it to work. What other settings did you use in addition to no retractions? I bought a spool of MakerFlex a couple of months ago and haven't tried it yet.

In addition to the bearing end cap @tommyph1208 mentioned, there is also this one with a screw to adjust the play: https://www.thingiverse.com/thing:54075 In my case, I simply used a couple of the spare 3mm washers that came in the UMO+ kit to provide some space between the shaft and the end cap. It's a little bit loose, but it has been working fine for almost a year.

The head on my UMO+ is not "very easy" to move. There is a little bit of resistance, but I can move it with one finger. Moving in one direction is easy; moving diagonally takes more force, but I can still do it with one finger (my index finger). I think the most important thing is that the resistance is constant along the travel.

To fit the 12864 LCD, you could get the dimensions from something like this: https://www.thingiverse.com/thing:293994 and modify the front panel file from github that @gr5 mentioned.

Sorry, I don't understand much German, so I had to translate your post and then respond in English . You should also check that the small wood pieces that cover the ends of the shafts are not rubbing on the shafts and causing drag. On my UMO+, I had to add washers between the frame and the wood shaft cover on one shaft to prevent rubbing.

If you look at the bottom of that "warped" print, is there evidence that the bottom layer has lifted off the bed? If so, you need to clean your print bed. If not, it's something else. What are your layer height settings? The initial layer is probably larger than the rest of the layers if you used default Cura settings.

The blobs might be happening because the nozzle is dragging the blob from the initial priming extrusion into the print. The blob should stick to the bed and be "wiped" off. If that is the cause, you might be able to grab the blob with some tweezers before it messes up your print. You could also have filament sticking to the nozzle. Wipe the nozzle while it's hot to clean off any excess filament. You could also try applying a small amount of silicone oil to the nozzle periodically to keep filament from sticking. Regarding the "warp", I think you mean the first layer is lifting off the bed. To fix that, the bed has to be really really clean, or you can try using a thin layer of glue stick spread out with a damp cloth. Try cleaning the bed again, and don't touch it with your bare fingers.

What is your first layer supposed to look like? Are those squiggles supposed to be there or should they be straight lines? Not being able to see what your printer is doing, my guess would also be your bed leveling is way off.

As @neotko states, you can buy cheap anti-backlash nuts at places like ebay for maybe 10USD. If your Z-linear bearings are good you probably don't need one, but it would be simple to make one using two nuts and a spring. The spring forces the edges of the nuts against one side, eliminating the backlash, rather than using gravity (the weight of the build platform) to accomplish that. This type of nut is often used in DIY CNC machines where backlash can't be tolerated because they operate in both directions rather than just one direction (down) as on our Ultimakers.

It would also be best to provide a sample wheel for whoever will model the part to measure. For that you will have to remove the wheel, which I bet will not be easy since they would be designed to be be very secure to keep small children safe.

There are also some printable versions of the 5.5mm hex wrench around, such as this: https://www.thingiverse.com/thing:1764237 If your printer is working well enough, that is...

@jarred Try these S3D profiles on your UMO+ as a starting point. You can easily turn support on or off, change the skirt to a brim, change the fill %, etc. https://www.dropbox.com/sh/r938yebz24j3uyq/AABJv2i2tr9bJzxsd4Fl09vza?dl=0

Unlike Cura, using S3D requires you to learn a lot about slicing and printer settings. The link that @neotko provided above is what I used to get started with S3D. Start out with the basic FFF profile that he provides and make adjustments from there. Read through the entire forum posting and go through all the FFF Settings screens to understand what they do. I still have a lot to learn, but I have been getting good prints from S3D on my UMO+ for a while now. I especially like the ability to customize supports and change settings mid-print. For most of my uses, Cura works great, but the S3D supports seem easier to remove. And now that I have some pretty good settings I have been using S3D quite a bit.

I second the recommendation of Tinkercad. It's easy to get started on and is fairly well oriented toward 3D printing.

Two grub screws 90° apart is what we used on medical equipment plus red loctite on the screws. Just hope that you don't have to remove them. 90° apart is better than 180° because they will push the shaft in one direction, rather than working against each other. The grub screws themselves are also pretty important. They have to be hard enough to grab the shafts well. In my UMO+ kit, a set of grub screws were supplied to replace the (cheap/soft?) ones that came with the pulleys.

Yes, I had to design and make a spool adapter for the Taulman 1-lb spool for my UMO+. The hole diameter is really small, something like 11mm.

@mjmdavis, From your photos it looks like you have constant z-axis banding that you are trying to solve. If so, replacing the sticking Z bearings may not solve the problem. The symptom of bad Z bearings is a bad layer at approximately 10-12mm height on the printed object, which shows up consistently. This is a result of the bearings sticking after direction reversal and that happens at about 10-12mm after the direction reversal, which you can see happening at the beginning of your video. Continuous horizontal banding is a different issue that has been discussed at length on this forum. Regardless of this however, changing your Z bearings to better quality ones that don't stick is a good move.